Patent Literature (PTL) 1 discloses examples of this kind of related art. In the publication, as illustrated in FIGS. 2A to 2C, an infrared sensor is disclosed which has a structure in which a sensor element equipped with an optical filter only transmitting infrared rays is covered with a resin except for the light-receiving surface. The sensor element is a quantum-type photodiode generating a photovoltaic effect using an infrared ray. In addition, the optical filter has a function of only transmitting an infrared ray having a specific wavelength.